Paper article



K. CLARK PAPER ARTICLE June 28, 1938 Filed April 11, 19:54

WMMMWEH Patented June 28, 1938 to American Seal-Kan Corporation of Delaware, Wilmington, DeL, a corporation of Delaware Application April 11, 1934, Serial No. 720,066

9 Claims.

This invention relates to paper articles and more particularly to those intended tocontact with foods. One example of such an article'isa milk bottle cap or closure,- and while it should be 5 understood that the invention is not to be rev stricted in its broadest aspects to closures for milk bottles, the invention. will be hereinafter more particularly described with relation to such use.

In many cases it is desirable to-use colors in connection-with such articles, as for the purpose of producing ornamental efiects or for distinguishing between grades or types of milk. For example, one color may be used in connection be ,used in connection with bottles containing certified milk, another color for bottles containwith bottles containing cream, another color may plastic conditionso that they interfelt with each other in amanner well known in manufacture of multi-ply paper.

It is,of course, important that in the manufacturing processes in making the caps, be so carried out that the facing of the paper stock which contains the color forms the outside face of the cap, and in order to insure this and to 1 insure ready handling of the paper in its various ing buttermilk, and so on, through the various gr'adesand qualities for which suchdesignations may be desired. Likewise it may be desired that certain colors be used exclusively by certain dairies, particularly in any given district, in order that the pro-ducts of the various dairies may be readily distinguished. Likewise in some localities 5 the use of 'coloredlettering is employed on the bottles themselves and it then may be desirable to employ sealing caps presenting'the same color as the letters on the bottles.

In most cases, however, it is undesirable that contact with colored paper material, not only because with the use of certain coloring mate- According to this invention, therefore, the caps are formed of a paper material which presents exteriorly the desired color but which on the opposite face presents material entirely free from coloring material. In order to accomplish this purpose the paper used is preferablyof multi-ply stock, one face portion only being colored, the other face portion being. free from coloring matapplication of coloring matter to the stock 'of one or more of the plies before the plies are brought together to form the completed paper, the several layers of material being brought together while they are in awet and more or less the food products themselves should come into stages of formation, certain methods of handling. 10 the paper have been found highly desirable as will later more fully appear.

For. a more complete understanding of this invention, reference may be had tothe accompanying drawing in which Figure 1 is a diagrammatic side elevation of a vmultiple cylinder paper machine arranged for sheeting a paper in accordance with this invention.

Figure. 2 is a fragmentary perspective of a 20 multi-ply paper suchas is produced by the mechanism shown in Figure 1 and which forms the basic material from which the caps are made.

Figure 3 is a diagrammatic view illustrating the cutting of the paper into blanks from which. the caps are made and certain subsequent treatments to which these blanks may be subjected before forming them into caps.

Figure 4 is a fragmentary perspective showing a blankv asin the condition subsequent to treatment'by the apparatus of Figure 3.

Figure 5 is a diagrammatic representation of a manner of supporting and feeding the several blanks to the cap-forming dies.

' Figure 6 is a perspective partly broken away hi one form of completed'cap'.

Referring first to Figure 1, at I, 2 and 3 are shown the several vats containing the paper stock from which'the several plies of the paper are to be made.- As shownthe vat l contains a stock 40 which is colored by any suitable means, such, for example, as a pigment-or a die of the desired color. -A more detail discussion ofthe desirable characteristics of such coloring will be given later. The vats 2 and 3 are shown as containing uncolored stock which should be of such a nature thatit contains no substances such as would be The use of multi-ply paper permits the r of plies will later appear.

deleterious to the food product with which it is to contact. While threeseparate vats are illustrated by which a three-ply paper may be made, it should, of course, be understood that any desirednumber might be used. Further.reference to the desirability of any particular number As shown, each one of the vats contains a pick- 5 which picks up the stock from its respective vat and applies it to the under face of the usual blanket l which passes successively over and in contact with the molds 4, 5, and 6, being pressed thereagainst by suitable couch rolls 8, 9 and ill. The blanket then passes about a suction roll or other similar device as at H for the purpose of more completely removing the water from the stock and from which it passes over suitable supporting rolls l2, between the press rolls l3 and M, the blanket returning around the roll it while the sheeted paper passes to the drier indicated conventionally at I? from which it may be fed 01? to any suitable device, for example, a winder shown at It.

The paper thus produced is illustrated in Figure 2 and comprises a colored lamination and two uncolored laminations 2i and 22. Paper for use as milk bottle caps and which is subjected to a severe molding action when being died to form should be of a somewhat open and porous nature so that it can be' readily impregnated by materials such as water and waterproofing or resistant materials such as wax, which not only facilitate the molding operation; but also render the caps when completed substantially waterproof.

It has been found in practice that it is most advantageous to have substantially only onethird of the total paper by weight or thickness colored. If there is less than this, the uncolored portion of the paper wil1 tend to show through on the colored side, particularly where the paper is subjected to substantial forming operations when being molded, which tends to produce undesirable surface abrasions or local thinning free from color. If the amount of colored stock is more than one-half of the total, there is a tendency for the color to show through the uncolored side, particularly after waxing, to suclr an extent that it will give the appearance of being present on that side of the article which is brought into direct contact with the milk, which alsois undesirable. While the most satisfactory proportions of thickness of colored and uncolored stock is generally about 1 to 2, this may vary from, according to conditions, of, say, about 1 to 3 to 1 to 1, with the thickness of paper most suitable for molding into milk bottle caps.

As the paper is subjected to moistening, as well as the wax treatment, in order to facilitate the molding operation, it is, of course, necessary that the color should be thoroughly set soas to prevent bleeding of coloring matter into themcolored portions or plies of the paper. Furthermore, as the articles when in use may become moistened by contactwith the milk, any such bleeding or fiow of the color might have a very deleterious efiect and even might escape into the milk. The sealed milk bottles are also subjected to other conditions of great severity with relation to coloring material in the caps, such, for example, as the icing operations which not only subject the caps to the action of cold water but also to abrasive actions of the ice. Two classes of coloring material are the most satisfactory, these being pigments, and dyes of the type known as direct dyes. 'Such dyes have a great aflinity for sulphite pulp such as is most suitable as abasic stock material for bottle caps, and they may be thoroughly set by the use of a hot salt solution. Most dyes used in papermaking are set by alum, but for paper which is to be impregmated with waxes or the like, the use of alum is sometimes disadvantageous, and unless a. size is up cylinder or cylinder mold such as d, 5 and 6,

employed with alum, the retention of the color and the setting efiect by the alum is less eficient. Where pigments are employed the use of a small amount of size helps to retain the pigment, but of course this detracts to some extent, at least, from the open and porous character of the paper and the ease with which it may be impregnated with the wax. With the use of direct dyes the salt which is used in setting them is easily washed out and has no bad effect on the paper stock and such dyes do not bleed into the wax as is the case with many dyes commonly-used in papermaking. Not only would such bleeding into the wax be disadvantageous in that the color might spread through theuncolored portions of the paper, but it might also contaminate the wax in the treating tank through which the blanks pass and thus pass into subsequently treated blanks in those tions where color is not desired.

In order to make a paper satisfactory for the molding operations, it is also advantageous to hold the degree of saturating qualities and the tensile strengths in directions longitudinally and crosswise of the paper within proper limits, these limits depending somewhat on the severity of the stresses produced by the molding operations, which are in turn dependent on the amount of deformation which the paper must undergo during such molding.

The paper thus prepared may then be subjected to treatment both to condition it for resistance to moisture and for the molding operation to which it must be subjected in forming it into the caps. In Figure 3 is shown diagrammaticallyv an apparatus by which the paper is cut into blanks and impregnated with the desired waterproofing agents and otherwise conditions for the molding operation. As shown in this figure, the paper is led from a suitable supply source, herein shown as the roll 30, through a punching mechanism indicated at 3|, by which blanks of the proper size are severed from the sheet material, the waste portions of thepaper being then removed as by being wound up into a roll 32 while the blanks 25 themselves are passed, as by the conveyor 33 to the impregnating tank 34. Sometime previous to being incorporated with the waterproofing materials, it is preferable to subject either the blanks or the paper to a moistening action which swells the fibers ,of the paper and softens it so that it may be more easily formed between molding dies, and this moistening is done preferably prior to the treatment for moisture resistance, since it may aid in the impregnating operation. Agents which may add to the strength or hardness of the completed caps or add other desirable qualities may be added to the treating water, if desired. The blanks in moist condition are shown, therefore, as being fed in between confronting faces of reticulated feeding belts 35 and 36, the recticulations permitting the water-resistant material, such as a suitable wax or mixture of waxes in molten condition, to find ready access to opposite faces of the blanks. By

condensation of the moisture vapor therein, acts to draw in the wax from the blank surfaces, resulting in a more thorough penetration of the wax into the interstices and perhaps even into the fibers moval from the tank are permitted to 'cool and wall 41 at its margin for engagement with the of the paper. The blanks after reare then deposited in any suitable (receptacles. It is then preferable to-permit the moistened and saturated blanks to stand for a time in order that they may become conditioned or tempered and uniformly sufliciently plastic to be most suitable for the molding operations. For this purpose they maybe kept in closed containers for a few hours.

When properly conditioned they may be subjected to the forming action between suitable dies as has been illustrated diagrammatically .in'.

be as illustrated in Figure 6 at 45. For example,

the cap thus formedmay have a central diskshaped portion 46 which bridges the neck of the milk bottle, this portion 46 having an upstanding inner face of a milk bottle above the usual diskreceiving ledge therein, an outwardly turned portion 48 covering over the pouring lip of the bottle, and a skirt. 49 depending therefrom to engage the outer face of the pouring lip. The entire outer face of the cap presents the desired color while the entire inner face of the cap is of uncolored stock so that no colored stock is presented where it may contact with the milk in the bottle.

In connection with the feeding of the cap blanks from the container 40 so that they may be delivered as desired to the forming dies, it is important that the blanks should be so positioned relative to the feed plate 4| that at each reciprocation it may engage'the lowest blank in the stack and remove it from the tube 40. There is a tendency in making blanks of a suitable thickness for formation into bottle caps for the blanks to dish through unequal rates of drying at opposite face portions thereof, or from other causes. Shouldsuch a slightly dished blank be presented with its convex face downward, this may cause difliculty in the. feeding action by reason of the feeding plate so thatthe blanks willbe removed successively from the bottomof the stack as desired. It

' will be noted, however, that the blanks must be presented to=the forming dies right side up so colored faces.

that the colored face shall always appear on the outside rather than the'inside of the cap, and it is therefore necessary, toinsure proper feeding with such a mechanism, that provision bemade so that the convex face of the blankshall always I the conditioned blank than the stock forming the remainder of the blank. This may be accomplished either through controlling the relative shrinkages of the two types of stock in the formation and drying of the paper, or through controlling the relative amounts to which these surface portions will be expanded by the saturating process, or through combinations of both. For

example, this may be done by controlling the relative freeness or slowness of the colored and'uncolored stock, as, by controlling the amount of heating to which the stock is subjected before it is employed in papermaking. Thus, if the un colored stock is slower than the colored stock, the

uncolored side of the paper tends to take up less water than the colored side. It expands less and therefore is on the concave side of the paper. Another'factor which may be of use is the rate of cooling'of the blanks on the two sides after-they leave the saturating tank. With the uncolored side up, the colored side being against the face of the conveyor, the uncolored side cools the more rapidly and assists in cupping the blanks in the proper direction. This is illustrated in Figure 3 where the direction of cupping is changed as the urating tank and is therefore less transparent, so

that the probability of the color from the colored side showing through is reduced.

It is also important, particularly from the standpoint of color and uniformity of color, that the completed blanks be quite accurate in thickness as the thickness of the blanksdetermines the action of the parts of the die thereon which are relatively spaced by predetermined dimensions. The amount of moisture-and the amount of saturating material, as also the amount of the paper stock, is thus of importance sinceall these factors determine the thickness of the blank when it reaches the forming dies. If the blank isnot thick enough the color, of the blank itself will show up in the completed article. blank is highly compressed during the forming operations, the color effect is deepened and where the compression is produced through a wiping action of the dies thereon, a glossy deeply colored finish is produced, different from that of the colored face of the blank before being molded. By

Where the suitable disposition of the excess stock which 1 must be compressed in the molding operation ornamental variations in shading may be produced. For example, areas of deeper color 50 separated by areas of. lighter color in pattern formation as indicated in Figure 6 may be produced, producing a pleasing ornamental effect.

' From the foregoing descriptionof a preferred constructionand a method by which it may be made it should be understood by those skilled in the art that various changes and modifications,

might be made without departing from the spirit or scope'of this invention as defined by the appended claims. I v v I claim: 1. A paper blank for molding into an article, said blank containing colored, and uncolored stocks in different portions, the colored stock" stock, said blank being impregnated with waterproofing material.

3. A wax paper blank for molding into an article, said blank containing throughout one face portion colored paper stock and in another face portion uncolored paper stock,the uncoloredpaper stock being slower than the colored paper stock.

4. A water-repellant paper milk bottle cap presenting uncolored relatively slow paper stock in contact with the bottle contents, and a colored outer face layer of a colored paper stock freer than said uncolored stock. 7

5. An interfelted multi-ply paper blank having stock of difierent degrees of freeness in opposite surface plies.

6. A Wax paper article made from a laminated paper blank, the laminations at opposite faces of the blank being of difierent degrees of freeness, the lamination containing the freer stock containing the larger proportion of wax and the stock being colored.

7. A molded paper article having a central disk and a marginal portion of generally inverted U shape in cross section extending upwardly therefrom, said article comprising interfelted laminations, the top lamination comprising colored paper stock in a continuous layer, and the bottom lamination being free from colored stock.

8. A molded paper milk bottle cap having a marginal portion of generally inverted U shape in cross section and forming a housing for the bottle pouring lip when the cap is applied to the bottle, said cap comprising interfelted laminations, the top lamination comprising colored paper stock in acontinuous layer, and the bottom lamination being free from colored stock, said colored lamination being colored throughout and of sufficient thickness to avoid formation of surface abrasions and local thinning free from color by the molding operation;

9. A molded paper milk bottle cap having a .marginal portion of generally inverted U shape in cross section and forming a housing for the bottle pouring lip when the cap is applied to the bottle, said cap comprising interfelted lam i- KEMPTON CLARK. 

